EPOCH, or ERA (Gr. brox0, epoche, epoch, pause). In history, a fixed point of time, commonly selected on account of some remark able event by which it has been distinguished, and which is made the beginning or determining point of a particular year from which all other years, whether preceding or ensuing, are com puted. Some writers distinguish between the terms epoch and era. According to them, both mark important events, but an era is an epoch which is chronologically dated from; an epoch is not marked in this way. The birth of Christ was thus both an epoch and an era from this point of view.
The more important historical epochs are here enumerated. For further details on the mode of reckoning see CALENDAR.
The Creation.The biblical record of the creation has formed the foundation of numer ous chronologies. Of course the authorities (Jewish and Christian) on these various modes of reckoning do not agree as to the time signi fied by the common authority for the event dated from. The more important of these epochs, of which there are about 140 different varieties, are (1) The epoch adopted by Bossuet, Ussher and other Catholic and Protestant divines, which places the creation in 4004 B.C. (2) The Era of Constantinople (adopted by Russia), 5508 B.C. The civil year begins 1 September, the ecclesiastical year about the end of March. (3) The Era of Antioch, used till 284 a.n, placed the creation 5502 B.C. It was merged irPthe following year in (4) The Era of Alexandria, which made the creation 5492 B.c. This is also the Abyssinian Era. (5) Jewish Era. The common era of the Jews places the creation in 3760 B.C. Their year is lunar-solar, that is, lunar with intercalary months, forming a cycle of 19 years, of which 12 have 12 months and seven 13 months. The year thus varies from 353 to 385 days. The civil year begins with the new moon following the autumn equinox. The eras dating from the creation are distinguished by the initials A. M. Const., Abyss., etc., are sometimes added to dis tinguish the particular epochs.
Julian Period. This begins 4713 B.c. It is an arbitrary epoch, fixed for the purpose of computing all dates forward, as in the case of the creation epochs.
The Olympiads. The Greeks computed their time by periods of four years, called Olympiads. Their year was lunar, with inter calary months. The first Olympiad, being the year to which Corcebus was victor in the Olym pic games, was in the year 776 B.c. The period of the commencement of the year, which was variable, was about July. The contraction used for the Olympic epoch is Olymph.
The Roman Era (Ab Urbe Condita). The Romans dated from the supposed era of the foundation of their city, 21 April, in the third year of the sixth Olympiad, or 753 B.c. (accord ing to some authorities 752 B.c.). This epoch is designated by the initials A. U. C. The Roman mode of computation was the foundation of our modern chronology.
Era of the Seleucidea. Begins 1 Oct. 312 B.C., the epoch when Seleucus I (Nicator) took possession of Babylon. The year consisted of 365 days, with a leap year every fourth year. This era is used in the book of Maccabees.
Spanish Era. This dates from 1 Jan. 38 B.C. The months and days were the same as those of the Julian calendar. It was disused in Aragon in 150; in Valencia, 1358; in Castile, 1383; in Portugal, about 1415.
Christian Era. Our mode of computing from supposed data of the birth of Christ was first introduced in the 6th century, and had not been generally adopted until the year 1000. Since the first year of the 1st century was 1 A.D., the last year of the same century was 100 A.D. Similarly the year 1900 A.D. was the last year of the 19th century. The same holds good in reckoning backward. For particulars of the mode of reckoning the years of the Christian era and the changes which it has undergone, see CALENDAR.
Armenian Era. This began 7 July 552, and was superseded by the Julian era about 1330. The year consisted of only 365 days.